Semiconductor devices are used in a large number of electronic devices, such as computers, cell phones, and others. Semiconductor devices comprise integrated circuits that are formed on semiconductor wafers by depositing many types of thin films of material over the semiconductor wafers, and patterning the thin films of material to form the integrated circuits. Integrated circuits include field-effect transistors (FETs) such as metal oxide semiconductor (MOS) transistors.
As the demand for smaller electronic products grows, manufacturers and others in the electronics industry continually seek ways to reduce the size of integrated circuits used in the electronic products. In that regard, three-dimensional type integrated circuit packaging techniques have been developed and used.
One packaging technique that has been developed is Package-on-Package (PoP). As the name implies, PoP is a semiconductor packaging innovation that involves stacking one package on top of another package. In PoP package designs, the top package may be interconnected to the bottom package by reflowing a solder paste disposed on opposing copper bumps to form an electrical connection between the packages.
Corresponding numerals and symbols in the different figures generally refer to corresponding parts unless otherwise indicated. The figures are drawn to clearly illustrate the relevant aspects of the embodiments and are not necessarily drawn to scale.